1. Field of the Invention
The present invention relates to a vehicular lamp and more particularly to a vehicular lamp that uses a light-emitting diode as its light source and as a means for melting snow and ice on the outer lens.
2. Description of the Related Art
In one type of the known vehicular lamps, a plurality of lamp units, each comprising, among others, a lens and a reflector and having a light-emitting diode (LED) used as its light source, are installed in the lamp body. A desired light distribution is obtained by combining a direct light emitting type lamp unit and a reflective light emitting type lamp unit.
Regarding the heat caused by lighting up the light-emitting diode, a heat sink or the like is used so that the generated heat is dissipated to the outside of the lamp chamber.
However, when the light-emitting diode is used as a light source, there is not much temperature increase by the radiation of light to the outer lens, and snow and ice on the outer surface of the outer lens do not easily melt.
More specifically, in a vehicular lamp with an incandescent light bulb, it is possible to melt the snow by the heat of the light ray transferred to the outer lens; however, light-emitting diodes do not produce heat in great deal. A radiation measure for that is nonetheless necessary, and there is a need to utilize the heat of light-emitting diodes effectively. Use of, for instance, a heat source such as a heater is conceivable to eliminate snow and ice from the outer lens of the lamp; but if the heat generated by the light-emitting diode can be actively used, it is preferable to use light-emitting diodes in terms of energy conservation and cost and the like.